An OLED (organic light-emitting diode) device can emit light by itself through an organic layer, because the OLED device does not need a back light, the OLED device has a faster response time and a greater viewing angle. Besides, the OLED device also has the advantages of higher contrast, lighter weight, low power consumption, and the OLED device is considered as the panel display device with the greatest development potential.
OLED is formed by multiple layers for different functions. There is very important of original property and compatible property for each of material. In multiple structure, usually includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL) and an electron injection layer (EIL) and so on. Please refer to FIG. 1, based on a multi-color OLED has red, green, blue three colors which could adjust different thickness layer of different layers for adjusting microcavity effect of OLED element and achieve to enhance light emission efficiency and narrow the spectral width of each color. For example, adjusting thickness of hole transport layer (HTL) of red/green/blue colors to adjust spectral width of these three color for balance color effect. In this design, HTL could not be deposited as common layer, it needs to add a process for using fine metal mask. It will increase time of manufacture and enhance cost of OLED according to the problem of wash fine metal mask. And, also induce alignment issue while using fine metal mask which decrease successful rate of OLED.